[lucy dog]

What about a spray bottle with vinager or something in it that won't hurt either one of them. Just be uncomfortable for Champ with a STRONG leave it command from her.

Like you said, you will have to teach her the command also. Just a couple of practices with her and her favorite treats and you can have her bellowing a deep scruffy LEAVE IT for herself. You may have to back her up with the spray bottle untill Champ gets it. A day or so of yelling and getting sprayed with water or whatever should do it.

I am not sure if it would work but just an idea. good luck!!